1. Field of the Invention
The present invention relates to a semiconductor device.
2. Description of the Related Art
US2011/0284956A1 discloses a semiconductor device that includes an LDMOS (Laterally Diffused MOS)-type transistor. This semiconductor device includes a p-type semiconductor substrate, an n-type semiconductor layer that is formed on the semiconductor substrate, a p-type drain offset region that is formed in a front surface portion of the semiconductor layer, an n-type body region that is formed in the front surface portion of the semiconductor layer so as to penetrate the drain offset region, a p-type source region that is formed in a front surface portion of the body region, a p-type drain region that is formed apart from the body region, a gate insulating film that is formed on the drain offset region so as to cross the body region from an end portion of the source region on the side of the drain region, a thick insulating film that is formed on the drain offset region between the gate insulating film and the drain region and a gate electrode that is formed on the gate insulating film. In this configuration, a boundary between the body region and the semiconductor layer is in contact with the gate insulating film.